Synthesis of Laurylchitosan and Its Use in the Separation of Flavonoids from Aleurites moluccana by Matrix Solid-Phase Dispersion

Chitosan was modified with lauroyl chloride to prepare a solid support for the application of matrix solid-phase dispersion (MSPD) for the extraction of flavonoids from the medicinal plant Aleurites moluccana. The laurylchitosan prepared by the homogenous and heterogeneous method, was characterized using analytical methods such as potentiometric titration and infrared spectroscopy. The hydrophobic properties were studied by naphthalene incorporation. The MSPD performance was evaluated by extraction of swertisin and 2″-O-rhamnosylswertisin from the leaves of A. moluccana.     

N,N′‐Bis­[tris­(hydroxy­methyl)­methyl]­ethanedi­amide: six O—H⃛O hydrogen bonds generate only a two‐­dimensional structure

Molecules of the title compound, C₁₀H₂₀N₂O₈, adopt a conformation which is almost centrosymmetric. The mol­ecules are disordered over two sets of sites with an occupancy ratio of 0.94:0.06. In the major form, there are two intramolecular O—H?O hydrogen bonds [O?O 2.756 (4) and 2.765 (4) Å; O—H?O 144 and 146°], in which the two amidic O atoms act as acceptors. In addition, there are four intermolecular O—H?O hydrogen bonds [O?O 2.650 (3)–2.666 (3) Å; O—H?O 158–171°]; these link each mol­ecule to six others in a continuous sheet structure which contains five distinct ring motifs, two of the S(7) type, two of the R(10) type and one of the R(22) type.     

Functionalized Benzofurans via Microwave‐Promoted Tandem Claisen‐Rearrangement/5‐endo‐dig Cyclization

Ortho‐allyloxy alkinyl benzenes undergo, upon microwave irradiation in dimethylformamide, a tandem sequence of Claisen‐rearrangement and 5‐endo‐dig cyclization to furnish 7‐allyl‐substituted benzofurans. With terminal alkynes, chroman‐4‐ones and enaminoketones become the main products. A mechanistic proposal for this observation relies on a reaction of the starting material with the solvent dimethylformamide under the microwave conditions.     

In vitro antibacterial and time-kill assay of ethanolic extract of Davilla nitida bark on multidrug resistant bacteria isolated from diabetic foot lesions

This study reported the antimicrobial activity of the bark extract of Davilla nitida on multidrug resistant bacteria isolated from Diabetic Foot Infections. Antibacterial activity of the bark extract was evaluated by agar Disk-Diffusion (DD), Broth Dilution (BD), Checkerboard and Time-kill methods. The extract showed a significant antibacterial activity against all groups of bacteria tested. BD was more sensitive for determining the antibacterial activity of the bark extract than the DD method. The bark extract inhibited the growth of bacteria with high-levels of antibiotic-resistance, such as Pseudomonas spp. (100.0%), Enterobacer spp. (88.89%), Staphylococcus aureus (54.55%), Streptococcus pneumoniae (75.0%), Staphylococcus saprophyticus (92.86%). The combination of extract with antibiotics resulted in an additive effect against most of the strains tested. Time-kill kinetics profiles of bark extract showed bactericidal and time-dependent properties. Our results suggest that the bark extract of Davilla nitida is a source of bioactive compounds, which may be useful against antibiotic-resistant bacteria.     

Dehydrodimerization of iodobenzenes to iodinated biaryls

The molybdenum pentachloride-mediated oxidative coupling of iodo-substituted electron rich benzenes without the loss of the iodo-substituents is reported. The presented methodology is an environmentally friendly alternative to known thallium(III)- and lead(IV)-reagents. Even 2,2',6,6'-tetraiodobiphenyl derivatives are easily accessible.